http://www.epa.gov/otaq/highway-diesel/index.htm
http://www.epa.gov/cleandiesel/documents/420f10027.pdf
http://read.dmtmag.com/i/42794/41
http://www.meca.org/galleries/files/Filter_Maintenance_White_Paper_605_final.pdf
http://www.dieselnet.com/tech/dpf_ash.php
http://fr.slideshare.net/biodieselautomotive/clean-diesel-and-aftertreatment-2